[llvm] 58b10df - DebugInfo: Move SectionLabel tracking into CU's addRange

[David Blaikie via llvm-commits]

Author: David Blaikie
Date: 2020-01-17T18:12:34-08:00
New Revision: 58b10df54ffdbfcd94ca0882a4adea0d375cb69d

URL: https://github.com/llvm/llvm-project/commit/58b10df54ffdbfcd94ca0882a4adea0d375cb69d
DIFF: https://github.com/llvm/llvm-project/commit/58b10df54ffdbfcd94ca0882a4adea0d375cb69d.diff

LOG: DebugInfo: Move SectionLabel tracking into CU's addRange

This makes the SectionLabel handling more resilient - specifically for
future PROPELLER work which will have more CU ranges (rather than just
one per function).

Ultimately it might be nice to make this more general/resilient to
arbitrary labels (rather than relying on the labels being created for CU
ranges & then being reused by ranges, loclists, and possibly other
addresses). It's possible that other (non-rnglist/loclist) uses of
addresses will need the addresses to be in SectionLabels earlier (eg:
move the CU.addRange to be done on function begin, rather than function
end, so during function emission they are already populated for other
use).

Added: 
    

Modified: 
    llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
    llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
    llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 69a39d55910d..c4e86df078b2 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -328,6 +328,8 @@ DIE *DwarfCompileUnit::getOrCreateCommonBlock(
 }
 
 void DwarfCompileUnit::addRange(RangeSpan Range) {
+  DD->insertSectionLabel(Range.Begin);
+
   bool SameAsPrevCU = this == DD->getPrevCU();
   DD->setPrevCU(this);
   // If we have no current ranges just add the range and return, otherwise,

diff  --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 922c43881d22..0280370d2d82 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1833,9 +1833,6 @@ void DwarfDebug::beginFunctionImpl(const MachineFunction *MF) {
   if (SP->getUnit()->getEmissionKind() == DICompileUnit::NoDebug)
     return;
 
-  SectionLabels.insert(std::make_pair(&Asm->getFunctionBegin()->getSection(),
-                                      Asm->getFunctionBegin()));
-
   DwarfCompileUnit &CU = getOrCreateDwarfCompileUnit(SP->getUnit());
 
   // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
@@ -2532,8 +2529,9 @@ void DwarfDebug::emitDebugLocDWO() {
       // offset_pair, so the implementations can't really share much since they
       // need to use 
diff erent representations)
       // * as of October 2018, at least
-      // Ideally/in v5, this could use SectionLabels to reuse existing addresses
-      // in the address pool to minimize object size/relocations.
+      //
+      // In v5 (see emitLocList), this uses SectionLabels to reuse existing
+      // addresses in the address pool to minimize object size/relocations.
       Asm->emitInt8(dwarf::DW_LLE_startx_length);
       unsigned idx = AddrPool.getIndex(Entry.Begin);
       Asm->EmitULEB128(idx);
@@ -3077,3 +3075,6 @@ uint16_t DwarfDebug::getDwarfVersion() const {
 const MCSymbol *DwarfDebug::getSectionLabel(const MCSection *S) {
   return SectionLabels.find(S)->second;
 }
+void DwarfDebug::insertSectionLabel(const MCSymbol *S) {
+  SectionLabels.insert(std::make_pair(&S->getSection(), S));
+}

diff  --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index fd82b1f98055..a44960589d89 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -768,6 +768,7 @@ class DwarfDebug : public DebugHandlerBase {
 
   void addSectionLabel(const MCSymbol *Sym);
   const MCSymbol *getSectionLabel(const MCSection *S);
+  void insertSectionLabel(const MCSymbol *S);
 
   static void emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT,
                                 const DbgValueLoc &Value,